What conditions apply to the use of ceiling-supported luminaires?

Ceiling-supported luminaires are required to be securely fastened and capable of supporting their weight without relying on additional support. This requirement is crucial for safety and functionality. When luminaires are mounted to the ceiling, they must be installed in such a way that they can withstand various forces, including those from vibrations, potential impacts, and the weight of the fixture itself, as well as the bulbs and any additional components.

Ensuring that these fixtures are appropriately secured minimizes the risk of them falling, which could lead to injuries or property damage. The NEC emphasizes adherence to safety standards in electrical installations, making it essential that any luminaire mounted at height is installed to be stable and secure.

The other options, while they may pertain to different aspects of lighting design or use, do not constitute essential safety requirements in the same way that the structural integrity and secure fastening of ceiling-supported luminaires do. Therefore, the condition about securely fastening and supporting the weight of the luminaires is foundational to their safe use in building applications.